<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
<button id="btn">按钮</button>
<script>
let a = 1;
const btn = document.getElementById('btn');
// async  异步事件执行函数 存到 event loop 池子中
// js是事件驱动的语言
btn.addEventListener('click',()=>{
    console.log('--------------');
})
btn.addEventListener('click',()=>{
    console.log('+++++++++++++++');
})
console.log('1111');
</script>
</body>
</html>